Experimental observation of symmetry protected bound state in the radiation continuum in the periodic array of ceramic disks

Abstract

We observe experimentally symmetry protected bound states in the continuum (BICs) in the stack of ceramic disks. We analyze transformation of the resonant state into BIC with increasing of the number of disks theoretically and experimentally. In the experiment we measure the transmission spectra through the array of ceramic disks at GHz frequencies. We observe a quadratic growth of the Q-factor of quasi-BIC with the number of disks due to material losses. We cross-check the observation of BIC in the transmission spectra by measurement of the field profiles which are a good agreement with the results of the numerical simulations.